export {}

/* 
  类型别名
    - 就是为类型起的别名，使用type关键字来创建
    - 注意：类型别名不能重名
*/

type str = string
type bool = boolean
type strOrNumOrBool = string | number | boolean

let a: strOrNumOrBool

interface Named {
  name: string
}

interface Aged {
  age: number
}

type Person = Named & Aged
